Reducing repository size

[kosua20]

After many modifications of the resources files, and even if most of them were removed in recent commits and moved to the auxiliary repository, the initial cloning still takes a lot of time because internal git data contains those files. I've run the BFG-repo-cleaner, which means the repository history was rewritten. If you have a clone or fork and you want to pull and merge a recent version of master, you might run into cloning errors. In that case, you will have to clone/fork again and reapply your changes.

Apologies for the inconvenience, but this helped the initial clone go from 160MB to less than 20MB.